phi nodes. It is called from MergeBlockIntoPredecessor which is
called from GVN, which claims to preserve these.
I'm skeptical that this is the actual problem behind PR8954, but
this is a stab in the right direction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123222 91177308-0d34-0410-b5e6-96231b3b80d8
RecursivelyDeleteDeadPHINode, and DeleteDeadPHIs return a flag
indicating whether they made any changes.
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makes several optimization passes abort in cases where they're currently
silently miscompiling code.
Remove the indirectbr assertion from SplitEdge. Indirectbr is only
a problem for critical edges, and SplitEdge defers to SplitCriticalEdge
to handle those, and SplitCriticalEdge has its own assertion for
indirectbr.
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when BB2 has its address taken. Since it ends up doing BB2->rauw(BB1),
this can cause the address of the entry block to be taken. Since it is
generally undesirable to nuke blocks whose address is taken, even when
we can, just unconditionally stop this xform.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85708 91177308-0d34-0410-b5e6-96231b3b80d8
MergeBlockIntoPredecessor. This makes SimplifyCFG slightly more aggressive,
and makes it unnecessary for LoopUnroll to have its own copy of this code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85667 91177308-0d34-0410-b5e6-96231b3b80d8
where a loop's header is being split and it has predecessors which are not
contained by the most-nested loop which contains the loop.
This fixes PR5235.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84505 91177308-0d34-0410-b5e6-96231b3b80d8
that get created during loop unswitching, and fix SplitBlockPredecessors'
LCSSA updating code to create new PHIs instead of trying to just move
existing ones.
Also, optimize Loop::verifyLoop, since it gets called a lot. Use
searches on a sorted list of blocks instead of calling the "contains"
function, as is done in other places in the Loop class, since "contains"
does a linear search. Also, don't call verifyLoop from LoopSimplify or
LCSSA, as the PassManager is already calling verifyLoop as part of
LoopInfo's verifyAnalysis.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81221 91177308-0d34-0410-b5e6-96231b3b80d8
that these passes are properly preserved.
Fix several transformation passes that claimed to preserve LoopSimplify
form but weren't.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80926 91177308-0d34-0410-b5e6-96231b3b80d8
instead of a bool argument, and to do the dominator check itself.
This makes it eaiser to use when DominatorTree information is
available.
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and introduce a new Instruction::isIdenticalTo which tests for full
identity, including the SubclassOptionalData flags. Also, fix the
Instruction::clone implementations to preserve the SubclassOptionalData
flags. Finally, teach several optimizations how to handle
SubclassOptionalData correctly, given these changes.
This fixes the counterintuitive behavior of isIdenticalTo not comparing
the full value, and clone not returning an identical clone, as well as
some subtle bugs that could be caused by these.
Thanks to Nick Lewycky for reporting this, and for an initial patch!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80038 91177308-0d34-0410-b5e6-96231b3b80d8
This adds location info for all llvm_unreachable calls (which is a macro now) in
!NDEBUG builds.
In NDEBUG builds location info and the message is off (it only prints
"UREACHABLE executed").
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75640 91177308-0d34-0410-b5e6-96231b3b80d8
CallbackVH, with fixes. allUsesReplacedWith need to
walk the def-use chains and invalidate all users of a
value that is replaced. SCEVs of users need to be
recalcualted even if the new value is equivalent. Also,
make forgetLoopPHIs walk def-use chains, since any
SCEV that depends on a PHI should be recalculated when
more information about that PHI becomes available.
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makes ScalarEvolution::deleteValueFromRecords, and it's code that
subtly needed to be called before ReplaceAllUsesWith, unnecessary.
It also makes ValueDeletionListener unnecessary.
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of returning a list of pointers to Values that are deleted. This was
unsafe, because the pointers in the list are, by nature of what
RecursivelyDeleteDeadInstructions does, always dangling. Replace this
with a simple callback mechanism. This may eventually be removed if
all clients can reasonably be expected to use CallbackVH.
Use this to factor out the dead-phi-cycle-elimination code from LSR
utility function, and generalize it to use the
RecursivelyDeleteTriviallyDeadInstructions utility function.
This makes LSR more aggressive about eliminating dead PHI cycles;
adjust tests to either be less trivial or to simply expect fewer
instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70636 91177308-0d34-0410-b5e6-96231b3b80d8
use, check also for the case where it has two uses,
the other being a llvm.dbg.declare. This is needed so
debug info doesn't affect codegen.
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